This invention relates to improvements in and concerning a cord grommet made of a thermoplastic resin and put to use where a cord of an oblong cross section is led out of a perforation formed in a panel such as a chassis, rear cover or case of an electric appliance, for the purpose of fastening the cord stably to the perforation in the panel for thereby minimizing possible electric interference between the cord and the panel, preventing the insulating coat of the cord from being damaged by the edge of the perforation in the panel and intercepting any pulling force exerted on the cord and thereby protecting the cord against otherwise possible separation from the terminal of the internal electric element to which the cord is connected.
Heretofore, various types of cord grommets have been proposed for the purpose mentioned above. Typical of these cord grommets are those disclosed by the common assignee in U.S. Ser. Nos. 699,814, now U.S. Pat. No. 4,002,821; 701,834; and 707,808, now U.S Pat. No. 4,002,822. These cord grommets are invariably composed of two members which are brought into face-to-face contact with each other with a cord interposed therebetween, one of said two members having a grooved inner face and the other member having a protruding inner face matching said grooved inner face. When such a grommet is assembled by bringing the two members into the face-to-face union across the intervening cord and the assembled grommet is inserted through the perforation in the panel, the grommet can be retained in said assembled state wherein the cord is held in a zigzagged bent form by the groove and the protrusion of the two matched members.
With such a grommet, however, since the cord is forced to assume a zigzagged bent state because of the confrontation between the groove and the protrusion, there is a fair possibility that the inner electric wires will be broken where the cord forms a sharp bend or the insulating coat of the cord will be scraped off where the gap formed between the groove and the protrusion narrows down so much as to form a constriction. Further at the time that the grommet is inserted in its assembled state into the perforation in the panel, since the cord is heavily bent by the engagement of the groove and the protrusion of the two matched members across the cord, there is produced high resilient force in the cord. When the grommet is set in position into the perforation formed in the panel such as of an electric appliance or it is removed from said perforation, therefore, there is entailed a disadvantage that the user is compelled to rely on a special tool designed to hold the two members of the grommet in tight engagement.
One object of the present invention is to provide a grommet which enables a given cord to be readily set in position into the perforation in the panel such as of a mechanical device or removed from the perforation without use of any special tool and yet precludes possible breakage of electric wires, damage to the insulating coat, etc.